Sandblasting apparatus



May 22, 1945- 5. J. ,OECHSLE E'i' AL SAND-BLASTING APPARATUS Filed Jan. 18, 1944 2 Sheets-Sheet l INVENTOR.

Slx'rus $.OECHSLE BY dorm Mommas Patented May 22, 1945 SANDBLASTING APPARATUS Sixtus J. Oechsle, Philadelphia, and John N.

Chil

ds, Meadowbrook, Pa., assignors to Metalweld, Inc., Philadelphia, Pa., a norporatlon of Pennsylvania Application January 18, 1944, Serial No. 518,688

'1 Claims. (CI. 51-11) This invention relates to the art of sand-blasting and more particularly to improvements in the method of and apparatus for sand-blasting in which water is employed to wet the sand as it is projected against the surface to be treated.

Heretofore and prior to the present invention, the operation of sand-blasting as ordinarily performed involved the projection by air pressure of dry sand against the surface to be treated. This method of dry sand-blasting necessarily produced a great deal of dust which was not only annoying and often hazardous to the operator of the sand-blasting gun and to those in the immediate vicinity of the sand-blasting operation, requiring their use of protective masks, but also rendered the operation impracticable in many cases, as where it was desired to sand-blast surfaces in more or less closed interiors which might contain valuable and delicate apparatus and instruments which would be adversely afiected by sand dust. An example of this would be a ship which might require sand-blasting treatment of surfaces, both exterior and interior. In such case. dry sand-blasting would be quite objectionable because the'dust attending the operation would have very deleterious eflects not only upon the machinery and equipment of the ship undergoing the dry sand-blasting treatment, but also on that of any other ship that might be docked near it.

It is accordingly among the principal objects of the present invention to provide a method of and apparatus for wet sand-blasting in'which the creation of sand-dust is eifectively reduced, if not entirely eliminated.

A further .and important object of the present invention is to provide an improved constructionof sand-blasting apparatus which is so designed and operated as to draw into the stream of the pressure-projected sand, for intimate mixture therewith bysuction induced by said stream, water in suiiicient amount to wet the sand and to be carried by it to the surface to be sand-blasted, thus holding the sand-dust in. suspension in the wetted sand all without impairing in any respect the abrasive qualities of the sand.

Still another and important object is to provide a method of and apparatus for wet sand-blasting wherein water is entrained into a stream of sand to be projected therewith at high velocity against the surface to be treated, the water being continuously introduced into the sand stream at any desired rate constantly proportional to the rate of flow of the sand stream, and wherein a rustinhibiting or other liquid agent may be introduced 55 served that such nozzle generally comprises a into the water stream also at a pre-determined rate for admixture with the sand stream and conveyance by it to the surface to be treated, the said surface-treating agent being continuously drawn into the water stream through a suction action induced by the latter preliminarily to its introduction into the high-pressure sand jet. A still further object of the present invention is to so improve the construction of the sandblasting apparatus as to measurably prolong its operating life, this objective being accomplished primarily by providing the sand-blasting nozzle with a lining of .rubber which extends throughout the whole length of that portion of the nozzle which immediately embraces and receives the full impact of the high pressure sand jet.

Still other objects relating to economies of oper-- ation and construction of the sand-blasting device oi the present invention will appear more fully hereinafter, suchas the provision of a wetsand-blast nozzle which is simple and compact in design, efilcient and durable in operation and capable of manufacture at low cost.

It will be understood that the present invention consists substantially in the combination,

construction, location and relative arrangements of parts. as well as in the method of continuously projecting a wetted stream of sand against a surface to be treated, all as hereinafter described in detail, as shown in the accompanying drawings, and as finally pointed out in the appended claims.

In the said accompanying drawings, which show for purposes of illustration certain preferred constructions and arrangements embodying the principles of the present invention,

Figure 1 is a top elevational view of the sandblasting device;

Figure 2 is a longitudinal cross-sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a transverse sectional view taken onthelineHofFig'ure 2;

Figure lls aviewsimilar toFigure2butshowing a somewhat modified construction of the sandblasting device;

Figureliisaviewtakenonthe lineI-Ioi' Figures; and

l igureoisaschematioviewshowinginside elevation and in operative relation all of the essential parts employed in practicing the method of the present invention.

Referring now to the drawings and more particularly to Figures 1 to 3 thereof which show one of the preferred forms of sand-blast nozzle constructed in accordance with and embodying the principles of the present invention, it will be obmain tubular body portion l having an outwardly flared discharge end II and an internally flanged rear end l2 within which is adapted to be fitted an'inner nozzle tube l3. This inner nozzle tube I3 is longitudinally bored to provide a passage l4 for the projection therethrough of a stream of dry sand supplied from any suitable source under suflicient air pressure to cause said sand to be discharged from the tube l3 in the form of an outwardly flaring high velocity jet. such as is indicated by the reference numeral IS in Figure 2. To this end, the rear portion of the passage l4 through the tube I3 is of gradually decreasing diameter toward the point l6 from whence it continues forwardly in the form of a restricted passage of uniform diameter, the outer end of which terminates at a point spaced a substantial distance rearwardly of the discharge end of the outer tube Ill. The relative dimensions and arrangement of the outer and inner tubes l0 and II are such that as the high velocity jet of air and sand issues from the inner nozzle l3, a region of suction is created between the envelope of the jet and the surrounding wall of the outer tube II), this suction being such as is characteristically produced by suction jet pumps and other such jet devices.

As most clearly appears in Figures '2 and 3, the inner wall of the outer tube I0 is provided with a protective lining or coating il of rubber or other such material having the capability of resisting the abrasive action of the sand. Also, the inner nozzle l3 is preferably constructed of an outer shell within which is suitably fitted an inner shell I3 formed of any suitable material suitable for withstanding the abrasive action of sand for reasonably long periods of use.

Suitably secured to the outer tubular shell III of the sand-blasting nozzle is a concentric shell I! providing an annular space "3 between it and the outer surface of its supporting tube l0. Preferably, the shell I8 is integrally secured to the tube ID, as is most clearly shown in Figure 2, by annular welds |9|9 which respectively join the opposite ends of the shell IT to the body of the main tube H1. The length and arrangement of the tube relative to that of its supporting tube II) are such that the annular space l8 extends from a point well to the rear of the transverse plane of the discharge end of the inner tube l3 to a point well in advance of said plane, or, in other words, so that the said annular space I8 is substantially coextensive with and circumferentially embraces the annular zone of suction \created internally of the main tube III by the high velocity jet of air and sand issuing from the inner nozzle l3. Communication between the annular space I8 and the said suction zone is effected by way of a plurality of openings 20 formed in that portion of the tube III which is embraced by the outermost shell l1, these openings 20 being preferably arranged in longitudinally and circumferentially spaced relation with respect to the longitudinal axis of the nozzle and being each preferably so inclined with respect to said axis that the water is freely drawn from the annular space l8 into the suction region for intimate mixing with the sand and air jet l6.

The water jacket which surrounds the tube It is connected to a suitable supply of water by way of a rigid conduit 2| secured to the shell II as an integral part thereof, preferably by welding as at 22, the rear end of this conduit 2| being provided with suitable fitting 23 for attachment to a flexible hose 24 connected to the water supply. The rigid conduit 2| is preferably curved as is most clearly shown in Figure 2 to constitute it a supporting handle or grip for the sand-blasting nozzle, and it is provided intermediate its length with a suitable valve 25 for regulating the supply of water through the conduit 2| into the water jacket H! of the sand-blasting nozzle.

As also clearly appears in Figure 2, the inner nozzle l3, which is removably fitted within the rear end of the main water-jacketed tube H1, is retained in operative position during operation of the sand-blasting nozzle, preferably by means of the fitting 26 fixedly secured to and carried by the flexible conduit 21 which is connected to the supply of sand under suitable air pressure. This fitting 26 is provided witha pair of diametrically opposed slots 28 which are respectively adapted to interlock with a pair of elements 29 which project radially from diametrically opposite sides of the main tube I0, these slots and projections 2329 coacting to provide for a quick-detachable bayonet-and-slot type of connection between the fitting 26 and the rear end of the tube l0. A compressible gasket 30 of rubber or other such resilient material is interposed between the corresponding ends of the conduit 21 and the inner nozzle l3 so that when the parts are interlocked as shown in Figure 2, the irmer nozzle I3 is maintained in its operative position within the outer tube [0 and the sand-blasting nozzle is then in operative condition for use. It will be understood, of course, that any other suitable means may be provided for effectively interlocking the several parts together and accordingly, it will be understood that it is not intended to limit the present invention to the use of the bayonet-andslot type of connection shown for interlocking the sand conduit 21 to the main tube III of the sandblasting nozzle.

Figures 4 and 5 show a somewhat modified construction of sand-blasting nozzle. In this modified construction, the main outer tube of the sand-blasting nozzle generally comprises a suitable length of rubber-lined hose 3| within the rear end of which is adapted to be fitted the inner sand Jet nozzle 32, which latter is similar in all material respects to the nozzle l3 of Figure 2. Secured to the rubber-lined main discharge tube 3|, as by the securing elements 33, is a rigid tubular unit of metal formed of a pair of axially spaced tubular elements 34 and 35 of equal diameter secured together by an intermediate tubular shell 36 of somewhat larger diameter, the shell 38 being concentrically arranged with respect to the axially spaced elements 34 and 35 and being integrally secured to the latter by the annular welds 31-31 to provide an annular chamber 33 immediately surrounding that portion of the main tube 3| extending between the axially spaced elements 34 and 35. Suitable openings 36 are provided in this intermediate portion of the tubular discharge hose 3| to effect communication between the annular water chamber 33 and the suction zone located interiorly of the tube 3|.

As in the form of sand-blasting nozzle previously described, this water chamber 33 is connected to a suitably shaped rigid conduit 43 having a fitting 4| at its outer extremity for facilitating coupling it to a flexible hose 4: leading to a suitable supply of water, the rigid conduit 40 being also supplied, as in the case of the conduit 2| of the previously described construction of sand-blasting nozzle, with a "regulating valve 43 for controlling the flow of water into the nozzle. In all other material respects the sand-blasting nozzle of Figures 4'and is the-same as that previously described, the advantage of its construction residing in the fact that the main discharge tube 3i thereof is formed of a length of rubberlined hose which is cut to suitable length and then provided with the apertures 39, following which it is adapted to be slipped into and secured within the tubular assembly consisting essentially of the several elements 34, 35 and I6. Obviously, maintenance, repair and servicing of the sand-blasting nozzle of the form shown in Figures 4 and 5 is easily effected due to the tact that the tubular section of the hose 3|, which constitutes the main discharge tube of the home, is subject to easy removal and replacement on I the job, should that be necessary.

in which is contained a suitable supply of dry sand D. Compressed air of suitable pressure is delivered by way of the conduit E into the top of the receptacle C to force the sand out of the latter and through the conduit B to the nozzle A, the supply 01! this sand under such pressure being controlled by asuitable valve F included in the line B.

The water chamber surrounding the main tube of the nozzle A it of Figure 2, or 38 of Figure 4) design. the proportion of the surface treating I agent derived from container J to the total volumeof the solution delivered to the sand-blasting nozzle may be maintained substantially constant, e. g. a water solution containing 5 percent by volume of a liquid rust inhibiting agent. Also, by virtue of the fact that the water delivered by the conduit G to the sand-blasting nozzle is introducedinto the dry Send by the suction action induced by the high velocity sand and air jet, it will be apparent that the proportion of water to the dry sand will be maintained constant so long as the rates of supply of these materials to the nozzle remain unchanged. Should it be desired to vary the proportion of water to sand, the. water regulating valve immediately associated with the sand-blasting nozzle (valve 25 of Figure 2, or valve of Figure 4) may be adjusted to increase or decrease, as desired, the amount of water delivered to the nozzle. Or, this valve may be operated to entirely shut off the supp y of water should it be desired to resort to the use of dry sand.

is connected to a suitable supply of water (not t 'the' form of an outwardly flaring high velocity jet, there is createdwithin the main tube of the It will be understood, of course, that the present invention is susceptible of various changes and modifications which may be made from time to time without departing from the general principles or real spirit thereof, and it is accordingly intended to claim the same broadly, as well as specifically, as indicated by the appended claims.

What is-claimed as new and useful is:

1.- In an apparatus for effecting wet sand-blasting, a combining nozzle for intimately mixing dry sand and water comprising a main discharge tube for the wetted sand, 9. sand-Jet-producing nozzle fitted in one end of said tube. and having a bore therethrough coaxial with the tube, an

annular water jacket surrounding said tube adapted for connection to a continuous supply of sand-blasting nozzle within the region immediately embraced by the annular-water space a region of suction byvirtue of which the water delivered by way of the conduit G is drawn into and intimately mixes with the jet of sand, and air whereby to wet the sand preliminarily to its final discharge from the sand-blasting nozzle. The result is that the dust, whichis a normal product of dry sand-blasting, is eliminated without impairing in any respect the abrasive action of the sand upon the surface against which it is directed.

In those cases where it is desired to specially treat the surface undergoing sand-blasting. as

- where it may be desired to coat said surface with a rust inhibiting agent, such agent may be introduced into the water stream preliminarily to its entrainmentand mixture with the sand and air jet. This is readily accomplished by including in the water line G a water jet eductor H of any suitable type and construction well known in the art having a tube I which is extended into a suitable receptacle J containing a supply K or a liquid rust inhibitor or other such surface treating agent. As an example or such an agent is a solution consisting of emulsified oil and a suitable detergent, or a solution of dichromate and/or phosphoric acid. The pressure of the water as it passes through the jet eductor H induces a suction therein which acts to draw the water, said tube constituting the inner wall of said annular water jacket and having a plurality of openings therethrough affording communica- .tion between the water jacket and the interior of said tube, and means for continuously delivering a supply of sand under pressure to said nozzle for mixture with the water drawn from said water jacket.

2. In a combining nozzle for intimately mixing dry sand and water, a main tubular member, a sand-Jet nozzle fitted in one end or said member and having a restricted bore terminating short of the opposite discharge end of the tubular member, said nozzle being adapted to project a high velocity outwardly flaring jet of sand axially toward and through said discharge end of the tubular member, and an outer shell disposed in spaced relation about said tubular member to form an annular water Jacket thereabout, the inner wall of said Jacket having openings communicating with the interior oi said tubular member whereby water delivered to said jacket may be drawn therefrom interiorly oi the tubular member for mixing with the sand jet preliminarily to its final discharge from the combining nozzle.

3. In a combining nozzle of the character delined in claim 2 wherein said tubular member is internally lined throughout with a rubber lining.

4. In a combining nozzle of the character defined in claim 2 wherein the outer shell of the water jacket is integrally secured to the main tubular member constituting the inner wall or said Jacket by annular welds respectively joining opposite ends of the outer shell to said tubular member.

5. In a combining nozzle of the character defined in claim 2 wherein said annular water jacket is provided with a rigid water inlet conduit shaped to provide a convenient handle for the nozzle.

6. In a combining nozzle for intimately mixing dry sand and water, a main tubular member formed of a replaceable length of rubber-lined conduit, a water-jacket assembly externally fitted on said conduit intermediate the opposite ends thereof, said assembly including a pair of axially spaced tubular members of equal diameters snugly fitting said conduit and a third tubular member of greater diameter bridging the space between said first pair of members and integrally secured thereto to provide the outer shell of an annular water chamber, the said conduit forming the inner wall of the water chamber and being provided with openings affording communication betweenthe water chamber and the interior oi the conduit, and a sand-jet nozzle fitted in one end of said conduit and having a restricted bore terminating within the zone encompassed by said affording communication between the interiors of the water-jacket and the conduit, a sand-jet nozzle fitted in one end of the conduit and having a restricted bore terminating within the zone encompassed by said water jacket, and means for delivering continuous supplies of water and sand to said jacket and jet nozzle, respectively, and'ior causing-the water to be introduced into the sand jet by the suction induced by the latter within said conduit.

SIX'I'US J. OECHSLE.

JOHN N. CHILDS. 

